In the Lindner et al U.S. Pat. No. 4,086,958 a latent-heat accumulator has been described, in which a latent heat storage medium, for example Glauber's salt, is alternately present in the liquid and solid state. For "charging" the latent-heat accumulator the latter is fed with a heat exchanger medium which is not miscible with the heat storage medium, for example a special oil, which during its passage through the storage medium transfers heat thereto and causes it to melt. The specifically lighter heat exchanger medium collects above the heat storage medium and can be recycled therefrom to a heat source.
For discharging, again a non-miscible heat exchanger medium is employed, which on passing through the heat storage medium extracts heat therefrom, during which the heat storage medium changes into the solid state. The heat exchanger medium heated up in this manner collects above the heat storage medium and can be conveyed therefrom to a consumer unit.
In the known apparatus, provision is made by an appropriate arrangement of the feed apertures of the heat exchanger medium to ensure that, for achieving a heat transfer as efficient as possible between the heat exchanger medium and the heat storage medium, the heat exchanger medium has to cover a path as long as possible within the heat storage medium. Preferably, the heat exchanger medium is introduced at the bottom of the storage container into the heat storage medium and traverses the entire depth of the latter in the form of small droplets or the like.
It has been found, that during prolonged operation of such a latent-heat accumulator, heat exchanger medium is retained to an increasing extent in the solid-phase zone of the heat storage medium, so that the position of the boundary surface between the heat storage medium and the heat exchanger medium is progressively displaced during continued operation. This gives rise to the danger of pipes, fittings and secondary heat exchangers becoming blocked.